Evaluate the safety and immunogenicity of priming with TBC-3B, which consists of live, recombinant vaccinia virus expressing the env and gag/pol genes of HIV-1 strain followed by boosting with HIV-1 recombinant gp120 strain MN vaccine formulated in alum, in healthy HIV-1 uninfected adult voluteers who who have never previously received vaccinia virus. We are currently in the follow up phase of this study.